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Phase Identification and Balancing in LV Distribution Networks Using Smart Meters Data
, M.Sc. Thesis Sharif University of Technology ; Safdarian, Amir (Supervisor)
Abstract
With the rapid proliferation of residential rooftop photovoltaic (PV) systems, current and voltage unbalance issues have become a matter of great concern in low voltage (LV) distribution feeders. This, however, necessitates identification of the hosting phase of the connected single-phase customers and PV panels. Both of the challenges have been addressed in this thesis. In the first place, this thesis proposes a mixed integer linear programming (MILP) model for phase identification problem. The model considers potential error in the input data provided by smart meters. To mitigate negative impacts of the error, the data associated with several consecutive time intervals are taken into...
Welding metallurgy of duplex stainless steel during resistance spot welding
, Article Welding Journal ; Volume 96, Issue 9 , 2017 , Pages 307s-318s ; 00432296 (ISSN) ; Pouranvari, M ; Movahedi, M ; Sharif University of Technology
Abstract
This paper investigates the metallurgical and mechanical response of 2304 duplex stainless steel-as an interesting candidate for automotive body-in-white applications-to resistance spot welding. The results showed the high cooling rate associated with the resistance spot welding process suppressed the postsolidification ferrite-austenite transformation leading to improper ferrite-austenite phase balance with a reduced volume fraction of austenite and consequent precipitation of chromium-rich nitrides. The effects of welding current, as the key parameter determining the weld heat input, on the austenite volume fraction and precipitation are discussed. The minimum fusion zone hardness...
Effect of welding heat-input on tensile strength and fracture location in upset resistance weld of martensitic stainless steel to duplex stainless steel rods
, Article Journal of Manufacturing Processes ; Volume 35 , 2018 , Pages 517-525 ; 15266125 (ISSN) ; Movahedi, M ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
Effect of welding current (2–4 kA) was investigated on the microstructure evolution and mechanical properties of the upset resistance dissimilar welds of Martensitic Stainless Steel (MSS) to Duplex Stainless Steel (DSS) rods. While in MSS side of the welds, no martensite was formed at lower welding currents (2–3 kA), small values of martensite was formed at the higher welding currents (3.5–4 kA). In DSS side of the welds, hotspot formation and change in the phase balance between ferrite and austenite phase were the most important phenomena. Strength of welds first increased and then decreased with welding current. Increase of strength was related to superior plastic deformation and stronger...
Pathways to improve the austenite–ferrite phase balance during resistance spot welding of duplex stainless steels
, Article Science and Technology of Welding and Joining ; Volume 24, Issue 1 , 2019 , Pages 8-15 ; 13621718 (ISSN) ; Pouranvari, M ; Movahedi, M ; Sharif University of Technology
Taylor and Francis Ltd
2019